Motorized toy vehicles have proven to be a consistent and popular product among young children over a wide range of ages. The design and character of such motorized toy vehicles has varied dramatically as practitioners have attempted to provide a variety of interesting and amusing toy vehicles. Generally speaking, such toy vehicles include a vehicle body and chassis within which a battery power supply and an electric drive motor are supported. Because of the characteristics of electric motors which generally operate best at higher speeds of revolution and with lower torque than the axle revolution speed practical in such toys, a speed reduction gear set or transmission is generally interposed between the driven axles and the motor output shaft.
One of the critical factors in successfully producing a battery driven toy vehicle is the attainment of performance of the vehicle while maintaining battery life. In many situations, these two objectives are somewhat incompatible in that high performance drive systems tend to use prohibitive amounts of battery power and therefore deplete the battery power supply quickly.
One of the critical elements in the design of such toy vehicles in attempting to meet a performance and battery life balancing is the selection of the gear ratios which couple the motor power to the driven axle. For example, a low gear ratio favors vehicle power and permits the use of a lower current motor which extends battery life. However, lower ratios in the vehicle drive gears limit the available speed of the vehicle and therefore reduce a desirable performance characteristic.
To further complicate the design of such toy vehicles, the vehicle in normal use encounters a great variation of surface and load characteristics. Thus, a child in a typical play pattern may often desire that the toy vehicle be able to climb substantial inclines on the one hand while providing high speed across flat surfaces on the other hand. This variation of loading for surface characteristic is usually more difficult and challenging for toy vehicles produced to replicate the so-called "monster trucks" or four-wheel drive trucks which the child user frequently desires to see replicate the climbing and power characteristics of the full-sized vehicles which they emulate. To provide a better balance between performance and battery life and meet the other operational variations imposed upon such toy vehicles, practitioners in the art have attempted to provide transmissions which may be switched between speed and power gear ratios by the child user. Most of such devices have provided a shift lever which extends from the vehicle body and which may be hand operated by the child user. While this provides some improvement in performance in that gear ratio may be varied, it often detracts from the play value of the toy vehicle by interposing an unrealistic physical configuration or appearance. There remains, therefore, a need in the art for an improved toy vehicle which meets the variety of operational circumstances in which such toy vehicles are required to perform and which, nonetheless, conserves battery life.